This invention concerns bag filling apparatus and, more particularly, apparatus for handling flexible intermediate bulk carriers (FIBCs, popularly known as big bags).
This invention particularly relates to bag filling apparatus of the type comprising a filling head, a structure providing suspension points for suspending a bag in registry with the filling head and a rigging arrangement for sealing the bag with the filling head, the rigging arrangement including a rigging ring for use in locating an inlet of the bag. Such apparatus is herein referred to as xe2x80x9ca bag filling machine of the type referred toxe2x80x9d.
An FIBC comprises a flexible bag which, at its upper inlet end, is provided with four flexible loops of fabric by means of which the bag is suspended from the suspension points of the support structure. The FIBC typically incorporates a liner forming an inlet opening or spout for attachment to the filling head. Usually, during filling, the bag is suspended over a table (optionally a vibratory table) located beneath the filling head for contact with the underside of the bag.
The current practice when filing FIBCs involves the operator rigging the empty FIBC and internal liner to the filling machine prior to filling. This involves locating and securing the four FIBC loops at appropriate suspension points and then feeding the spout of the FIBC liner through the rigging ring and wrapping the liner spout about this ring to secure its position. The liner is then sealed against the filling head by inflating an inflation bladder that is fixed to the lower part of the filling head.
When filling small FIBCs (FIBCs with a seam height of 1200 mm or less), the operator can perform the rigging operation from floor level. However if the FIBC is of a larger size (e.g. 1200 mm or above), then the operator cannot reach high enough to rig the FIBC. This can be overcome by use of a raised platform to enable the operator to reach the filling head and FIBC suspension points. The use of a raised operating platform is undesirable for the following reasons:
the platform takes up floor space
the cost of the platform can be expensive
the rigging of an FIBC from raised platform is unergonomic for the operator
An alternative approach is to mount the the filling head on the apparatus in such a way that it is raised and lowered along with the bag suspension points. This is not desirable, as it requires the use of a long length of flexible pipe to feed into the filling head with the product to be supplied to the FIBC. Long lengths of pipe are considered to be unhygienic and may have a detrimental effect on the accuracy of the weighing system used to determine the weight of material introduced into the FIBC.
An objective of the present invention is to facilitate floor-level rigging of a range of FIBC sizes, even larger FIBCs having a seam height of 1200 mm or more.
According to the present invention there is provided a bag filling apparatus of the type referred to in which the support structure and the rigging ring are movable independently of the filling head between a lower position facilitating rigging of the bag loops and the bag inlet to the suspension points and the rigging ring and an upper position in which the bag loops are raised and the rigging ring is registered with the filling head.
The rigging ring may be carried by the support structure.
Movement of the support structure between its lower and upper positions may be effected by a suitable drive such as fluid powered piston and cylinder assembly or assemblies.
The filling head may be mounted for vertical adjustment to accommodate bags of different heights.
Adjustment of the filling head may be effected by means of a drive arrangement such as a rack and pinion drive.
A device, e.g. a clamping device, may be provided for fixing the filling head in a selected position of adjustment.
The drive for raising and lowering the supporting structure may act to effect movement of the supporting structure relative to the filling head. For example, the raising and lowering drive may act between a carriage mounting the filling head for vertical adjustment on a generally vertical mast and the bag-supporting structure so that, when the filling head has been fixed in a selected position of adjustment, the bag-supporting structure can when required be moved relative to filling head to accommodate rigging followed by subsequent raising of the bag for registration with the filling head
The filling head may be fitted with an inflatable bladder for co-operation with the rigging ring in order to seal the bag inlet to the filling head, the sealing engagement usually being sufficient to prevent spillage of product and escape of dust.
The invention will now be described further by way of example only with reference to the accompanying drawings, in which: